#ifndef __LENGTH_H__ 
#define __LENGTH_H__
#include <Quantity.h>

class UnitLen;
extern const UnitLen& INCH;//base unit
extern const UnitLen& YARD;
extern const UnitLen& FEET;
extern const UnitLen& MILE;

class Length:public Quantity
{
public:
	Length(double value, const UnitLen& unit);
    Length operator+(const Length & len) const; 
};

#endif

